15W Fm-transmitter
It was five years ago when I did an attempt to build my first fm-transmitter. It ended in a giant faillure. The only thing it did was interferring with our tv-set. Looking back it was due to the lack...
View ArticleAM Transmitter
Notes: It is illegal to operate a radio transmitter without a license in most countries. This ircuit is deliberately limited in power output but will provide amplitude modulation (AM) of voice over the...
View ArticlePowerful AM transmitter
The circuit for a powerful AM transmitter using ceramic resonator/filter of 3.587 MHz is presented here. Resonators/filters of other frequencies such as 5.5 MHz, 7 MHz and 10.7 MHz may also be used....
View ArticleLong range FM transmitter
The power output of most of these circuits are very low because no power amplifier stages were incorporated. The transmitter circuit described here has an extra RF power amplifier stage, after the...
View ArticleCoilless FM transmitter !
The RF oscillator using the inverter N2 and 10.7Mhz ceramic filter is driving the parallel combination of N4 to N6 through N3.Since these inverters are in parallel the output impedance will be low so...
View ArticleWireless Telephone Bug
Here’s a neat little project that will allow you to monitor your phone line as soon as your phone is off hook. You can use a regular FM broadcast band radio to monitor the conversation. Just remember,...
View ArticleFM Telephone Bug
Here is a simple transmitter that when connected to a phone line, will transmit anything on that line (execpt the dial tone) to any FM radio. The frequency can be tuned from 88 to about 94Mhz and the...
View ArticlePhone Broadcaster
Here is a simple yet very useful circuit which can be used to eavesdrop on a telephone conversation. The circuit can also be used as a wireless telephone amplifier. One important feature of this...
View ArticleTransmitter FM 45W with valve
TECHNICAL CHARACTERISTICS: Tendency of catering: 220V AC Frequency of emission at FM: 88~108MHz Force of expense: max 45W (without the R3), R1 15KW/2W R2 1KW/10W R3 1KW/10W (for biggest force in the...
View ArticlePosistive one-shot
Posistive one-shot by 4528<cut> IC 4528 CMOS is dual monostable Multivibrator that can trig both rise ad fall edge. T1 and T2 use determine input timming,RST is reset and +/-IN is input tringger....
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